Immature kidneys unable to concentrate/dilute urine resulting in quick dehydration. 2. Fluid/electrolyte imbalance common due to higher percentage of H2O compared to body weight, high metabolism, and increased insensible fluid loss. 3. Tachycardia early sign of shock, Hypotension LATE sign of shock meaning at least 25% of their circulating blood volume is depleted 4. High risk for hypoglycemia due to decreased glycogen stores. 5. Diarhhea is a major cause of metabolic acidosis; MUST monitor potassium, glucose and calcium